1. Field
The field is packaging and in particular packaging for transporting and storing capillary columns.
2. Prior Art
Capillary columns or tubes, especially ones with integrated emitter or spray tips, are commonly used in the field of analytical chemistry for the chromatographic separation of mixtures that differ in their physical and chemical properties. In the field of liquid chromatography coupled with electrospray ionization mass spectrometry (ESI-MS), analytes are first loaded onto a capillary column, then separated by eluting them off the column at different time points, and subsequently sprayed through the tip into the mass spectrometer where they are analyzed. Typically these columns are installed on the liquid chromatography system with the tip end pointing towards the ion source of the mass spectrometer, within a distance of a few millimeters.
The integrity of the tip ends of the capillary columns greatly affects the ESI efficiency; thus the columns must be shipped, stored, and handled with great care. Typical capillary columns are very fine and not especially fragile, although their tips are very fragile. A capillary column is tubular, typically 360 μm (14 mils) in outer diameter, 50-100 μm (1.9-3.9 mils) in inner diameter, and 10-20 cm (3.9-7.8 in) in length, although other lengths and diameters are used. The tip is formed by tapering one end of the column or tube. A typical tip is shown in FIG. 3 at 135 and is typically 2 to 5 mm long and has inner and outer diameters varying between 1 and 10 μm (0.039-0.39 mils).
Prior art packaging and shipping containers for capillary columns usually comprised densely packed, specialized boxes such as those sold by New Objective, Inc., of Woburn, Mass. A user (researcher or lab technician) removed each column from the box with a rubber-tipped forceps. This required great care due to the high fragility of the tip, as illustrated by the New Objective website, which has the following instructions: “Avoid bending emitter (spray tip) towards you. Although polyimide-coated fused-silica is pliable, should you lose contact with the emitter it may snap back, causing damage to the tip.” Moreover, it is not practical to put the columns back into the box. Thus the boxes are used by the manufacturer for transporting the columns to the end user but generally are not used in the laboratory for storing columns.
In the laboratory, after removal from their shipping container and before use, the columns are often taped to workbench shelves or the outside of the shipping box. Alternatively, they are sometimes stored in test tubes with their tips extending upward from the test tube, exposing them to potential damage, as well as airborne dust, which can cause deteriorated ESI performance.
Insofar as we are aware, there is no satisfactory way of holding or storing and dispensing individual capillary columns safely, without the need for forceps, while protecting the columns, and especially their tips, from damage.